A document is found on Mars by archaeologists that speculates about the possibility of life on Earth
First published in "Holiday", May 1959.
| Date | Publication | Publisher | Type | Page | |
|---|---|---|---|---|---|
| 1959 | The Challenge of the Spaceship: Previews of Tomorrow's World | Harper & Brothers | Nonfiction | ||
| 1960 |
|
Über den Himmel hinaus: Unser Leben im Zeichen der Raumfahrt | Econ | Nonfiction | 179 |
| 1960 |
|
The Challenge of the Spaceship: Previews of Tomorrow's World | Frederick Muller Ltd | Nonfiction | |
| 1961 |
|
The Challenge of the Spaceship | Ballantine Books | Nonfiction | 133 |
| February 1962 |
|
Häpna!, februari 1962 | Grafiska Förlaget Kindberg & Söner | MAGAZINE | 7 |
| January 1972 |
|
Report on Planet Three and Other Speculations | Harper & Row | Nonfiction | 3 |
| 1973 |
|
Report on Planet Three and Other Speculations | Corgi Books / Transworld Publishers | Nonfiction | 13 |
| 1975 |
|
Report on Planet Three and Other Speculations | Corgi | Nonfiction | 13 |
| 1976 |
|
Strange Orbits | Blackie & Son | Anthology | 95 |
| 1978 |
|
S druge strane neba | Jugoslavija | Collection | 46 |
| June 1980 |
|
The Challenge of the Spaceship | Pocket Books | Nonfiction | 161 |
| June 1982 |
|
Report on Planet Three and Other Speculations | Signet / New American Library | Nonfiction | 11 |
| 1984 |
|
Report on Planet Three and Other Speculations | Pan Books | Nonfiction | 13 |
| 1985 |
|
Berichte über einen kleinen blauen Planeten | Bastei Lübbe | Nonfiction | 9 |
| 1985 |
|
Prvi kontakt | Književne novine | Collection | 9 |
| March 1985 | Report on Planet Three and Other Speculations | Berkley Books | Nonfiction | 3 | |
| 1988 |
|
S druge strane neba | Prosveta | Collection | 46 |
| July 1993 |
|
By Space Possessed: Essays on the Exploration of Space | Gollancz | Nonfiction | 139 |